Intravascular clots may form in a patient's vasculature for many reasons. For example, following various types of surgical procedures, as well as trauma, patients are prone to developing deep vein thrombosis (DVT). Patients suffering from hip, tibial and knee fractures undergoing orthopedic surgery, spinal cord injury, or stroke are especially at high risk.
Factors contributing to the development of intravascular clots, such as DVTs, include reduction of blood flow, vascular stasis, increase vessel wall contact time, coagulation changes, blood vessel damage, and pooling of blood in the lower extremities. It is believed that slowing of the blood flow or blood return system from the legs may be one of the main factors related to DVT with greatest effect during the intraoperative phase. Also of concern is the postoperative period. Even individuals immobilized during prolong travel on an airplane or automobile may be at risk.
Deep vein thrombosis may be systemically treated using anticoagulation drugs, catheter based thrombolysis, and/or thrombectomy procedures, with or without the use of a lytic agent. Catheter based thrombolysis is used predominantly to treat acute thrombosis (clot present <7-14 days), with thrombectomy indicated for removal of an acute to chronic thrombus (present >14 days), due to the increased formation of collagen within the clot. During treatment by thrombolysis, a tissue plasminogen activator (tPA), which is a clot specific thrombolytic, i.e., more effective in the resolution of acute clots by fibrinolysis than chronic clots, may be utilized. However, utilizing an agent like tPA is not suitable for all clots, including chronic clots.
Improved methods and agents for treating clots, including chronic clots, remain desirable.